Flux flow, pinning, and resistive behavior in superconducting networks
We have studied the behavior of fluctuation effects in superconducting systems using numerical simulations of XY and Coulomb gas models. The fluctuation of vortex lines in high temperature superconductors, in the presence of an external magnetic field, has been studied using a three dimensional XY model. We have carried out new simulations on a more dilute vortex line model than we considered previously, and find surprising evidence that the process of vortex line lattice melting occurs as two distinct phase transitions. As the vortex line lattice is heated, it melts first into a vortex line liquid of straight unentangled lines, having superconducting properties in the direction along the lines (parallel to the external field), but not in directions transverse to the lines. At a higher temperature, the thermal excitation of closed vortex line loops links all the lines together, leading to a tangled vortex line liquid, with completely normal metal properties in all directions. We have also continued simulations of the two dimensional Coulomb gas, as a model for vortex fluctuations in two dimensional arrays of Josephson junctions. We find phase transitions which do not have the critical behavior expected from standard symmetry analyses.
- Research Organization:
- Rochester Univ., NY (United States). Dept. of Physics and Astronomy
- Sponsoring Organization:
- DOE; USDOE, Washington, DC (United States)
- DOE Contract Number:
- FG02-89ER14017
- OSTI ID:
- 6958865
- Report Number(s):
- DOE/ER/14017-4; ON: DE93002707
- Country of Publication:
- United States
- Language:
- English
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Flux flow pinning and resistive behavior in superconducting networks
Flux flow, pinning, and resistive behavior in superconducting networks
Related Subjects
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Cermets
& Refractories-- Superconducting Properties-- (1992-)
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75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
DOCUMENT TYPES
FLUCTUATIONS
HIGH-TC SUPERCONDUCTORS
MAGNETIC FIELDS
MAGNETIC FLUX
MELTING
PHASE TRANSFORMATIONS
PROGRESS REPORT
SUPERCONDUCTORS
VARIATIONS